a person who likes something just because they have heard that someone else likes them. someone who wouldn't understand the meaning behind the lyrics or the thoughts and feelings. someone who says they are when they aren't and are so obviously following along. someone who is so fake it's sickening.

person1: so i'm gonna go buy this AFI cd.
person2: what's AFI?
person1: just this band i like.
person2: what does it stand for?

Someone who says they really like something when either
1: The barely know anything about it
2: They're only saying that to fit in

Posers usually all dress the same and think they're totally hardcore when really, they suck. Poser is becoming the new term for conformist, because most posers are only doing the annoying things they do to fit in.

EXAMPLE 1:
Poser: OMG I love Green Day!
Punk: What's your favorite album?
Poser: American Idiot.
Punk: Ha! Typical poser. I like Insomniac.
Poser: Wha? Is that a second name for one of their songs?
Punk: No, it's an album!
Poser: They have more albums???

EXAMPLE 2:
Poser: I have a girlfriend. *note: poser is a girl*
Non-Poser: So you're lez or bi or something?
Poser: No, I'm just expreimenting. That's okay in highschool.
Non-Poser: So you aren't attracted to girls but you're dating one?
Poser: Yeah, I love her. She's HOTT.
Non-Poser: You can't say that if you're not attracted to girls. It's faking it. You're a stupid poser. That's sick, it's not just a brand of clothes or something, you're probably breaking your "girlfriend's" heart, because you aren't really attracted to her. Get a boyfriend instead, or be single you fuckhead!
*note: I actually had that conversation with a stupid poser. Most of the posers I know pretend to be bi, and then they use the word "gay" as an antagonistic phrase.*

EXAMPLE 3:
Poser: I love My Chemical Romance!
Non-Poser: What's your favorite song?
Poser: Welcome to the Black Parade!
Non-Poser: Do you own any of the albums?
Poser: No, I just saw the video on TV! It was so cool... I love MCR <3333
Non-Poser: Have you ever heard "Cemetery Drive"?
Poser: No, I just heard them for the first time! My mom just bought me a MCR shirt!